This study was designed to measure the levels of serum and saliva ghrelin concentrations before and after surgery in an attempt to clarify whether this hormone plays any significant roles in acute appendicitis and cholelithiasis patients when compared with healthy controls. Samples were obtained from 20 patients with appendicitis, 10 patients with cholelithiasis before and after operation, and 16 healthy controls. The levels of ghrelin (acylated) were measured by means of a RIA assay. The results revealed that preoperative levels of ghrelin in saliva and serum were significantly decreased with respect to post-op in patients undergoing appendectomy, and control levels. This was also the case when the preoperative ghrelin concentrations in patients with appendicitis were compared with those having choelithiasis. Taken together, decreased ghrelin concentration in preoperative appendicitis might be a causative factor for the "loss of appetite" observed in an acute inflammatory condition such as acute appendicitis. However, further studies are necessary to reveal the exact mechanisms behind this observation.